German Chancellor Angela Merkel has welcomed the opportunity to discuss possible sanctions against Iran at the nuclear security summit starting in Washington Monday, according to dpa. "Time is pressing," Merkel said in Berlin before her departure. She was referring to debate on whether to penalize Iran for its failure to comply with International Atomic Energy Agency (IAEA) demands over its controversial nuclear programme. Iran meanwhile declared that it would ignore any resolutions passed by the summit in the US capital. Leaders from more than 40 states are gathering in Washington for a top-level summit on nuclear security hosted by US President Barack Obama. The talks will explore ways of safeguarding uranium and plutonium so it does not fall into the hands of terrorists. The chancellor said it was good that Russian President Dmitry Medvedev and Chinese President Hu Jintao would both be present at the Washington summit. Both countries have been reticent about applying sanctions to Iran. Merkel is to highlight the danger of civilian nuclear material - such as that stored in hospitals - being used to make so-called dirty bombs, which spread radioactive material by blowing it up with conventional explosives. The chancellor was also expected to present the measures Germany has taken to protect its nuclear material as an example to other countries. Germany only has civilian nuclear programmes. Merkel said she was looking forward to bilateral talks with Obama, which would focus on the military strategy in Afghanistan, the rekindling of climate change talks and financial market regulation. Merkel is not expected to make a firm offer for Germany to house freed inmates from the US prison camp at Guantanamo Bay on Cuba. Berlin had previously agreed to investigate individual cases of former Guantanamo detainees for whom it would not be safe to return to their countries of origin. "These discussions are still running," Merkel said ahead of her departure. Several of Germany's states have refused in advance to accept any former Guantanamo detainees. After the summit, the chancellor will continue her journey to the US state of California, where she is due to meet with scientists and business leaders.